Yeah, I guess they are currently messing around with their database system. The only kind of success I had with animations was by rendering single frames, and submitting animated *.gif files, what's a bad solution, regarding the small color palette, and poor compression of complex images.
But since I am using an outdated version of Opera (mainly because they refuse to roll out updates for Linux users), and did not find a good substitute by now, this could have been my fault too.
Thank you for providing a second case.
But as I am writing this, some memories of reading the DA FAQ come to mind, and I guess it could have been some issue, where you would need to be approved by the mods to submit video files, if I remember correctly.